I've never built a "smitty sled" (Nor do I really know what it is exactly). I have a Jet Sled Jr and plan on building something to get it off the ground and to strap my hub shanty on to the side of it. I have an idea as to what I want to do, but my biggest question is the ski's! Is there a difference between Downhill and Cross Country? Also, what do you use to screw the wood in to the ski's? I don't care about making it collapsible, Just want to be able to drag my sled easier and be able to fit more on like the hub shelter I got coming in the mail on Tuesday.